The present invention relates to a device for simultaneously measuring interference and wall thickness of a half cylindrical plain bearing which is applied on sliding parts of vehicles, ships, industrial equipments, office machines or acoustic apparatus.
Recently, requirements for quality, in particular, precision of half cylindrical plain bearings have become strict so that one hundred percent inspection is required upon shipment of such bearings. Japanese Utility Model Publication No. 29679/1960 and Japanese Patent Publication No. 20906/1976, both of which are owned by the applicant of this application, discloses a device for measuring interference of a half cylindrical plain bearing and a device for measuring wall thickness of such plain bearing, respectively. However, there has been no device so far which is capable of simultaneously measuring both interference and wall thickness of such plain bearing. Therefore, in the prior measurement of a half cylindrical plain bearing, separate devices have been needed to measure interference and wall thickness, thus making such measurement time-consuming and inefficient. Moreover, the prior measurement of wall thickness of such bearing involves the following disadvantages. For reasons in terms of functions, a half cylindrical plain bearing has a thicker wall thickness in the middle portion in a circumferential direction than in the remaining portions and has a slightly thin wall thickness near the end portions in the circumferential direction. Accordingly, wall thickness of a half cylindrical plain bearing is measured in the following manner. Firstly, wall thickness at a central point, points spaced therefrom by 30 degrees and by 60 degrees in circumferentially opposite directions, which points are positioned near one axial edge of the bearing, is measured in this order, and an operator memorizes the measurement at the central point and keeps a record of differences between the measurement at the central point and those at the points spaced therefrom by 30 degrees and 60 degrees in circumferentially opposite directions, which differences are mentally calculated. Thereafter, wall thickness at five points positioned near the other of the axial edges of the bearing is measured in a similar manner. As the above measurement of wall thickness is performed at ten points of the bearing, and an operator memorizes the measurements and calculates the differences between the measurements mentally, it takes about nine to ten seconds to measure wall thickness of a single plain bearing. Furthermore, a half cylindrical plain bearing receives undesirable depressions at its inner and outer peripheral surfaces upon measurement of its wall thickness by contacting with a pressing member and anvil of a measuring apparatus and a rod of a dial gauge.
As described above, in the prior art, interference and wall thickness of a half cylindrical plain bearing are measured by separate measuring devices, and much time and labor are required in the measurement. Moreover, depressions are disadvantageously produced on a half cylindrical plain bearing after measurement.